1. Field of the Invention
This invention relates to an automotive wheel structure. More particularly, this invention relates to a light weight and strong molded resilient fiber reinforced plastic automotive wheel structure having the mechanical functions and riding performance characteristics of conventional pneumatic tire and wheel assemblies at loads below the design load of the wheel structure, and whose mechanical functions and safety characteristics are superior to those of conventional pneumatic tire and wheel assemblies at loads above the design load of the wheel structure.
2. Prior Art
Heretofore, automotive vehicles have used a two component assembly which comprises a pneumatic tire positioned around a metal wheel. These conventional wheel assemblies suffer from a number of inherent disadvantages. One such disadvantage results from the two piece construction, which requires that the manufacturer of automotive vehicles purchase wheels from one supplier, and the pneumatic tires from another. Consequently, it is often necessary that the pneumatic tire or the wheel be manufactured to specifications to insure compatibility of the tire and wheel components. Thus, purchasing costs, including higher freight costs, cost of mounting pneumatic tires on the wheels, are maximized to the vehicle manufacturer, and, hence, to its customers.
A further disadvantage of the conventional pneumatic tire and wheel assembly resides in the excessive weight of the metal wheel, which increases the overall weight of the automotive vehicle. The increased vehicle weight usually results in decreased gas mileage.
Another disadvantage of the conventional pneumatic tire and wheel assembly resides in the pneumatic tire. Conventional pneumatic tires are subject to air loss when the tire is punctured by stones, metal objects, and other sharp objects which are often found on roadways. Punctured pneumatic tires cannot support the automotive vehicle unless repaired by those trained in the repair of punctured pneumatic tires. Such punctures often occur on the open highway, which requires that the automotive vehicle carry a spare pneumatic tire and wheel assembly, which decreases the space available for cargo and which adds significantly to the weight of the vehicle.
Thus, for many years, there has been a need for a non-pneumatic tire and wheel assembly for use in passenger cars and in off the road vehicles, such as farm and military equipment, as well as in aircraft, trucks and certain commercial vehicles. Prior efforts over the last several decades have generally resulted in substantially rigid structures that did not achieve the mechanical functions and the riding performance characteristics of conventional pneumatic tire and wheel assemblies.
An example of one prior effort is U.S. Pat. No. 2,016,095 issued Oct. 1, 1935 in which a solid tire tread is cured on stiffening hoops made of tough spring steel tubes which structure is then affixed to a disc wheel formed of sheet metal.
U.S. Pat. No. 3,807,474 discloses a high density, linear polyethylene hub structure carrying a locking rim onto which is molded a tire which may be solid or hollow having a cord insert of resilient material. The hub structure disclosed is of substantially rigid material, the tires providing the resilience.
British Pat. No. 1,013,214 discloses a vehicle wheel including a non-pneumatic tire having a bead clamped between substantially radially extending flanges provided on the rim, fabricated presumably of rigid metal. The resilence of the structure is provided by the means affixing the tread to the rim as well as the tread material itself.
All of the above prior attempts to provide a non-pneumatic tire and wheel assembly have failed to provide such a device having sufficient utility to make it commercially feasible. None of the prior art devices has achieved the mechanical functions and riding performance characteristics of a conventional pneumatic tire and wheel assembly.
Accordingly, it is an object of this invention to provide an automotive wheel structure having the mechanical functions and riding performance characteristics similar to a conventional pneumatic tire and wheel assembly at loads up through the design load of the wheel structure and tire.
It is another object of this invention to provide a wheel structure and integral non-pneumatic tire tread having mechanical functions and safety charcteristics that are superior to those of a conventional pneumatic tire and wheel assembly at loads above the design load of the wheel structure and tire.
It is still another object of this invention to provide a molded resilient fiber reinforced plastic automotive wheel structure and integral non-pneumatic tire tread which is of unitary construction, and which is light of weight and of high strength.
It is a further object of this invention to provide a wheel structure and integral non-pneumatic tire tread to simulate the appearance of a conventional tire and wheel assembly.
It is yet another object of this invention to provide a wheel structure and integral non-pneumatic tire tread having the mechanical functions and riding characteristics of a conventional pneumatic tire, but also having a lower rolling resistance.
Other objects and advantages of this invention will become apparent to those skilled in the art from the description to follow when read in conjunction with the drawings appended hereto.